.MSI to .WSI conversion

I have an interrogation regarding the size of the .wsi and .msi generated using the conversion tool Wise Package Studio 7.0 SP3 provides. I'm doing a cleanup of our sources. I'm creating .wsi and extracting source files from .msi that don't have any.

For example, I'm doing the conversion process with a 10 megs .msi. The .wsi generated is 5 megs and the .msi compiled from the .wsi created is 5 megs also. I would like to know why the .wsi is so big in size and why the .msi generated from that .wsi doesn't have the exact same size as the source .msi. All the files have been extracted from the .wsi. So if I convert a 200 megs .msi to a .wsi project (with files extracted), the .wsi is around 100 megs and the new .msi generated is around 100 megs also ...

Usually, the compiled .msi is half the size of the original .msi. What could cause that ? Is that normal or a problem ? Someone already experienced that ?

Answers

External CABs and external files out of the .WSI (not sure what you meant but it varies from one package to another).

No worries about storage here. I find it weird that the .MSI recompiled with the .WSI extracted from the source .MSI differ that much in size. And I was wondering if there could be any technical reasons behind (compression of old packages done with Install Shield).

Thx for your inputs. I compared both .MSI with MSI Diff and they have no differences at all (even if the recompiled one is half the size of the source one). And in others cases, when I do the comparaison, I have tons of line like this with change in one entry:

And it's all the same for every entry in the File table. The Attributes value is indexing from 16384 which means that files are compressed (msidbFilesAttributesCompressed) but I don't understand how files can be compressed and the .MSI be bigger than a .MSI where the files are not at all.

I don't understand how files can be compressed and the .MSI be bigger than a .MSI where the files are not at all. That attribute value means that they're compressed into an internal CAB file, i.e. they become part of the MSI, hence the size increase. If you were to choose to have those files compressed into an external CAB file, the size would decrease. Hopefully it follows that, in that instance, the resulting CAB would need to be distributed with the MSI.